Thirteen UCSC faculty members have come together to develop this application for the purchase of a state-of-the-art Finnigan LTQ Mass Spectrometer System (LTQ MS). This system consists of a high- performance 2D linear quadrupole ion trap mass spectrometer (LTQ). We are asking the NCRR to fund the purchase of this system to greatly expand and modernize our Mass Spectrometry MS Facility, which is dedicated to research in UCSC's Departments of Chemistry and Biochemistry (CBC), Molecular, Cell, and Developmental Biology (MCD), and Environmental Toxicology (ETOX). The shared MS Facility currently houses two mass spectrometers, while 2 additional mass spectrometers are housed in individual labs and available on request to the biomedical research faculty. While these instruments are well maintained, each has limitations that undercut its ability to support the quality and breadth of research that could otherwise be undertaken at this university. Without additional, updated equipment, our ability to provide our faculty with a first class research infrastructure will remain compromised. This problem will only become exacerbated in the future, as the biomedical research faculty of these four departments is projected to expand by 50% over the next decade. Acquisition of the LTQ MS will play a large role in alleviating these problems. The research initiatives of the ten major users can be divided into two broad areas. Each has far reaching implications for basic biological science, as well as for related biotechnology applications and the treatment of disease. The broad subject areas include: 1) ESI-Linear Ion-Trap based proteomics to study complex biochemical processes 2) ESI-Linear Ion-Trap approaches to understanding signal transduction pathways. The five major users in Area 1 (Fink, Holman, Lokey, Millhauser, and Smith) use proteomic methods on projects that depend on the resolution and sensitivity of the proposed instrument. Five other major users associated with Area 2 (Hartzog, Kellogg, Noller, Ottemann, and Tamkun) utilize this technology for biochemical cellular machinery characterization. Three Minor Users who will employ the instrument to investigate protein structure and function, and to clarify cellular mechanisms involved toxicology. [unreadable] [unreadable]